Vital signs effectively predict non-hypoglycaemia in patients with altered mental status in pre-hospital settings: A retrospective analysis

Abstract

BackgroundBlood glucose (BG) measurement by paramedics for patients with altered mental status is recommended as pre-hospital care in Japan. Therefore, paramedics prioritise BG measurement over transport to hospital even in emergency conditions such as hypotension or hypoxaemia. The purpose of this study was to examine the relationship between BG levels and vital signs, and to evaluate whether vital signs are effective in determining the necessity of BG measurement in pre-hospital settings. MethodsWe extracted data of patients who had BG measurements performed by paramedics in Kobe City from April 2015 to March 2019. We retrospectively investigated patient age, sex, presence of hypoglycaemia (BG level < 50 mg/dL) and vital signs. If a patient did not have hypoglycaemia and was transported to the Kobe City Medical Centre General Hospital, a final diagnosis was obtained. Patients aged below 15 years, and those with BG measurement errors, missing vital sign data, or a Japan Coma Scale 0 and I-digit codes were excluded. The χ2 test and Mann-Whitney U test were used for statistical analysis, and P<0.05 was considered statistically significant. ResultsOf the 1,791 patients, 1,242 were eligible for analysis (mean age, 71.9 years; 805 [58%] male). Hypoglycaemia was observed in 324 patients (26.1%). Of the 918 non-hypoglycaemic patients, 253 (27.6%) were transported to our hospital and stroke was the most common final diagnosis (61 patients [24.1%]). The non-hypoglycaemic group had more elderly patients than the hypoglycaemic group (median 73 vs. 76 years; P < 0.01). A significant difference in each vital sign were noted between hypoglycaemic and non-hypoglycaemic groups, with body temperature showing the highest difference between groups (area under the curve, 0.71; 95% confidence interval [CI], 0.68-0.74). Furthermore, in cases with systolic blood pressure being over 100 mmHg and body temperature being 38°C or less, it was highly unlikely that hypoglycaemia caused impaired consciousness (likelihood ratio 0.12 and 0.16; 95% CI 0.05-0.25 and 0.06-0.35, respectively). ConclusionWhen considering pre-hospital hypoglycaemia assessment, vital signs are an effective index. If patients have significant hypotension or high fever, paramedics should consider immediate transport rather than BG measurement.